The invention relates to a continuous casting plant for slabs comprising a water-cooled mould, from which the strand is continuously extracted, a supporting and guiding means with rollers that guide the strand between them and a cooling device with nozzles through which a coolant, for example water, is sprayed on the strand and the rollers.
It has been known (U.S. Pat. No. 3,766,968) to form a part of the cooling device by flat jet nozzles which are arranged parallel to the surface of the strand, i.e. to the broadside of the slab, their longitudinal axes being parallel to the axes of the rollers. This configuration of the cooling device aims at cooling the outer faces of the rollers facing the strand surface, which faces are exposed to an intensive heat radiation, and at preventing local thermal overstressing of the rollers. In this apparatus the flat jet nozzles are arranged outside of the slab edges between neighbouring rollers in alternating order at opposite slab edges each, so that the coolant jet of a flat jet nozzle is sprayed over the entire side of the slab from one edge to the other one. It has been shown that in the area of tertiary cooling of the strand, i.e. in the zone in which the cooling of the strand is not exclusively effected by direct spraying with water, but is effected mainly by removing the heat from the strand via the machine parts, a more intensive cooling is desired than is obtained by an alternating arrangement of the flat jet nozzles.